1. Field of the Invention
The present invention relates generally to hard copy apparatus. More specifically, the present invention relates to media size and position detection for a hard copy apparatus having a vacuum platen.
2. Description of Related Art
In the field of hard copy production, it is imperative Who to know the size and position of the print medium to be used. In ink-jet technology, as droplets of ink "fly" from the writing instrument to the print media, accurate print media positioning within an ink-jet hard copy apparatus print zone is even more critical. The art of ink-jet technology is relatively well developed. Commercial products such as computer printers, graphics plotters, copiers, and facsimile machines employ ink-jet technology for producing hard copy. The basics of this technology are disclosed, for example, in various articles in the Hewlett-Packard Journal, Vol. 36, No. 5 (May 1985), Vol. 39, No. 4 (August 1988), Vol. 39, No. 5 (October 1988), Vol. 43, No. 4 (August 1992), Vol. 43, No. 6 (December 1992) and Vol. 45, No.1 (February 1994) editions. Ink-jet devices are also described by W. J. Lloyd and H. T. Taub in Output Hardcopy [sic] Devices, chapter 13 (Ed. R. C. Durbeck and S. Sherr, Academic Press, San Diego, 1988). As providing background information, the foregoing documents are incorporated herein by reference.
Solutions to locate sheet media on a platen generally rely on mechanical or optical sensors. However, they are generally just a media-present or media-not-present condition indicator. None of those types of sensors create a true two dimensional profile of media on the platen.